Shimming basement subfloor?


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Old 12-03-03, 10:25 AM
G
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Shimming basement subfloor?

I am considering putting a subfloor in a portion of my unfinished basement in order to create a workout area. The area that would be covered is 1pprox 12'x18' and has a concrete floor. This is a 1920 house and the basement slopes significantly down to a center drain in the middle of the basement. I Used string to determine the largest deviation from the egdes down to the drain and it appears to be approx 3". What is the best/easiest way to get the subfloor level? Use 2 (2x4) shims? A 3" drop is too big for slef leveling masonry right? I also assume there is a reason for the drain and such a slope....so i don't want to defeat the purpose of the drain. Any thoughts are appreciated....
Thanks!
 
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Old 12-03-03, 01:38 PM
floorman
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you gonna build a wall at the deepest point?you can use self leveler if you build a damn where you want it to end at it's deepest point and you would have to make a couple pours but it can be done.Make you're damn and prime the floor at the deepest spot,mix and pour,let dry prime again mix and pour,and do that until you get the desired thickness at the deepest point then start working you're way to the shallow end.The problem as you may have figured out is the deep end what are you going to do to finish that off?
 
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Old 12-03-03, 01:52 PM
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reply to floorman

I do not plan on putting a wall on that edge right now. The space is bounded by the back and side wall of the basement and a existing framed wall on the other side. The side which has the 3" dip down from the corners will be exposed and ends roughly on the centerline of the basement. You are right...i will have quite a little step up onto the subfloor. There is a possibility that I might finish the rest of the basement (880 sq ft) someday in the future and the rest of the basement suffers from the same slope down to the center drain...can the self leveling masonry be busted up easier than concrete in the event that I need to remove it, or is it solid as concrete. I would also like to maintain some slope under the subfloor (<1/2") so that if I have some water intrusion there, it will at least drain. Can I apply concrete over self leveler in order to create this minimal slope? or should I just let the self leveler set some before applying it and shape it into the necessary slope?
Thanks for the feedback
 
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Old 12-03-03, 07:33 PM
DIMMike
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Answer some questions first.

Where is this located? State, area, and terrain of outside.

How long you been there?

What is the outside wall made of? 1920 does not suggest concrete, or very reliable concrete.

The reason I say this is because I had a friend with a 1950's house in Boston area where a once in 10 year rain swamped the grounds ability to absorb water and run off from a hill all ran off to the basement of his house. Never before an issue--that day major issue.

So before you undo what someone went to major issues to do. Think hard.
 
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Old 12-04-03, 10:20 AM
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reply to DIMMIke

It is a one-story, stucco bungalow in Portland, Oeregon and I have lived here for only about 6 months.

I know it is a concrete foundation because there is an old canning room in the front corner of the basement that has not had the wall s painted...I can't tell if it is poured or large blocks, but definitely concrete. I have had water come in through the foundation in this canning room after an overly-vigiorous watering of a plant close to the foundation on that corners. I amm going to clean, patch, seal and paint this ASAP (Bandaid approach, I know, but don't have the resources to excavate the founbdation now.

Definitely want to maintain some slope in the event of water, just not 3+ inches.

I will talk to neighbors who have been here for decasdes about past flooding issues in the neighborhood.

Great board...thanks for all the feedback!
 
  #6  
Old 12-04-03, 12:58 PM
brickeyee
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If the ceiling is high enough that you can live with leveling, consider using some pressure treated 2x lumber to level the floor. It is sort of a PITA to cut the slope into it, but will give you a solid floor and preserve the drainage. A 2x4 on edge every 16 inches with a inch plywood floor should work well. If you fasten plywood down with only a few screws you will be able to remove it and dry out the underside if water enters. If you seal up the area you are inviting a mold/mildew problem until you can make sure it is completely dry.
 
  #7  
Old 12-04-03, 08:02 PM
DIMMike
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A way

I realize this is messy but would handle the problem and give you a flat floor. A way (and its not trivial work) to alter the drainage is to
1. Rent a jackhammer ( and get some friends cause this is gruelling)
2. Make a through a foot-18" or so away from the wall.
3. Dig it out and remove broken concrete and put in pipe with drains at the corners and midpoints.
4. Level the inside of the rectangle and raise center drain.

If you try this be ABSOLUTELY certain you know where water, sewer, and gas pipes are. Code may require you to contact them so they tell you where they are.

Be aware #1 and #2 are VERY hard work and time consuming. A friend and I did less than half that dimesion in a day and I felt I had run 2 marathons and ached for days.

End result is flat and has good drainage.
You can mitigate outside by changing terrain by putting dirt against wall to add slope to move it away.
 
 

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